So Madame Merle went on, with much of the brilliancy of a woman who had long been a mistress of the art of conversation. But there were phases and gradations in her speech, not one of which was lost upon Isabel's ear, though her eyes were absent from her companion's face. She had not proceeded far before Isabel noted a sudden break in her voice, a lapse in her continuity, which was in itself a complete drama. This subtle modulation marked a momentous discovery—the perception of an entirely new attitude on the part of her listener. Madame Merle had guessed in the space of an instant that everything was at end between them, and in the space of another instant she had guessed the reason why. The person who stood there was not the same one she had seen hitherto,but was a very different person—a person who knew her secret. This discovery was tremendous, and from the moment she made it the most accomplished of women faltered and lost her courage. But only for that moment. Then the conscious stream of her perfect manner gathered itself again and flowed on as smoothly as might be to the end. But it was only because she had the end in view that she was able to proceed. She had been touched with a point that made her quiver, and she needed all the alertness of her will to repress her agitation. Her only safety was in her not betraying herself. She resisted this, but the startled quality of her voice refused to improve—she couldn't help it—while she heard herself say she hardly knew what. The tide of her confidence ebbed, and she was able only just to glide into port, faintly grazing the bottom.